Acetyl chloride → 5-Acetyl-4-methoxy-3-methyl-benzofuran-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To 4-methoxy-3-methyl-benzofuran-2-carboxylic acid tert-butyl ester (310 mg, 1.18 mmol) dissolved in 9 mL of chlorobenzene was added acetyl chloride (0.3 mL, 3.6 eq). The solution was cooled to <0° C. while titanium tetrachloride (0.61 mL, 4.8 eq) was added dropwise. The reaction mixture was stirred at 0° C. and below for 6 h and then heated in an 85° C. oil bath for 3.5 h. The reaction mixture was poured into ice/water, and the mixture was extracted with ethyl acetate. The combined organic solution was washed with 2N HCl and water. Removal of the solvents in vacuo gave 167 mg (57% yield) of 5-acetyl-4-methoxy-3-methyl-benzofuran-2-carboxylic acid.

Provenance & Evidence